Camera shutters-- techincal question

[Aquarium Dreams]

I like the shutter. I would miss it if it was gone.

 

[gmarquez]

I'm reviving this discussion, because I ran into this:

http://photo.net/bboard/q-and-a-fetch-msg?msg_id=00CaDT

Excerpt:
"Joseph Wisniewskiprolific poster, Jun 17, 2005; 09:43 a.m.

Ilkka nailed it. It is possible to build sensors that have "electronic shutters", as in the "interline transfer" CCD sensors used in Nikon D1 and D70. But these sensors need to be "cleared" in the dark before exposure, and should also be in the dark after exposure (during "readout", the transfer of data from the sensor to the camera electronics). This reduces smear and blooming...

...CCDs are two decade old, very mature technology. They are timed electronically, just like shutters have been timed electronically for the last couple of decades, to achieve accuracies not possible in the old fashioned mechanically timed shutters. In the Nikon D70 (a million unit/year selling DSLR) the shutter blades serve only as a "light blind", providing darkness for clearing and readout. The exposure is timed electronically, which lets it do things like 1/8000 sec top exposure and 1/500 sec x-sync while using the mechanism of a Nikon N70 shutter, built for 1/2000 sec top exposure and 1/90 sec x-sync."

 

[darich]

My Kodak P880, with the same image sensor size as my 20D's, has no shutter at all as it has a continuous electronic viewfinder.

I don't think the shutter and viewfinder are connected at all.
"continuous electronic viewfinder" - you mean the lcd screen on the back? So what happens when you switch that off? Is your viewfinder switched off?
Of course not - it's purely a screen that is unconnected to the shutter mechanism.
If they were connected and you switched off the screen, the shutter wouldn't work because you've claimed your camera "has no shutter at all BECAUSE it has a continuous electronic viewfinder"

And both cameras have a significant difference in their sensor size. As expected the Canon 20D sensor is WAY bigger. According to Stevesdigicams and dpreview the 20D sensor is 15.0 X 22.5 mm.
According to dpreview the Kodak sensor is minute in comparison measuring a mere 7.18 x 5.32 mm

My Kodak P880 will sync with flash at 1/4000th of a second

Where did you find this info???
Kodak website doesn't say it, neither does dpreview,stevesdigicams.
nor does [ame="http://www.amazon.com/Kodak-Easyshare-P880-Digital-Optical/dp/B000A8JYB8"]Amazon[/ame]

I'm not saying you're wrong but i'd be interested to hear where you got your info from considering the manufacturer doesn't even claim it.

And as for the mechanical shutter - i found this

Current DSLRs use mechanical shutters just like film cameras. That's not because it's the best way to construct a camera. It's because the technology is available and mature, and current full-frame CCD technology requires the sensor to be covered while it's read out. More advanced sensor technology does no longer need a shutter (as seen from today's digicams), but image quality does not reach that of full-frame CCDs. So with the quality-aware buyers of DSLRs, mechanical shutters are currently the right compromise.

You can read more here
I'm not sure how knwledgeable the guys is but it seems a reasonable explanation.

 

[Digital Matt]

The Nikon D70 works by turning on/off the sensor. This is why you can sync the flash at 1/500. The only thing I can think of as to why other cameras don't have this is limitation in the technology. Camera companies must be getting better results from using a mechanical shutter. I'm sure this will change at some point in the future.

 

[250Gimp]

So here is another angle on this question.....How do some DSLR's have the live view option (Pentax, or Olympus, I can't remember)? Does that mean there shutter is open before the shot or is there another sensor which controls the live view?

Just wondering..

 

[shorty6049]

i believe theres a splitter of some sort in the path of the light comming from the lens that sends light to a sensor that gives you the live preview